Novel noreremophilane derivatives

ABSTRACT

There are provided certain 2-oxygenated-6-isopropyldecalins, methyl substituted and unsaturated derivatives thereof which possess interesting and useful properties as odorants and flavorants.

United States Patent Bozzato et al.

[ l Apr. 29, 1975 Assignee: Givaudan Corporation, Clifton, NJ.

Filed: Sept. 21, 1973 Appl. No.: 399,595

Related U.S. Application Data Division of Ser. No. lll,736, Feb. I,1971, Pat. No. 3,819.7l l.

Foreign Application Priority Data Feb 19, I970 Switzerland 2394/70 U.S.Cl 260/586 F; 252/522; 260/6l7 F;

260/586 C Int. Cl. C07c 49/54 [58] Field of Search 260/586 R, 587, 586 F{56] References Cited UNITED STATES PATENTS 167L808 3/1954 Johnston etal. .l 260/586 R OTHER PUBLICATIONS Berlstein; Org. Chem," Vol. VII, Illsupplement, pp. 1259-1267, (1944).

Berlstein; Org. Chem." Vol. VII. Ill supplement, pp. 692-693. (I949).

Chem. Abstracts," Vol. 64, p. l4225a ([966).

Primary Examiner-Bernard Helfin Assistant ExaminerNorman MorgensternAtrornev, Agent, or Firm-Thomas Cifelli, Jr.

[57] ABSTRACT There are provided certain 2-oxygenated 6isopropyldecalins, methyl substituted and unsaturated derivativesthereof which possess interesting and use ful properties as odorants andflavorants.

4 Claims, No Drawings 1 NOVEL NOREREMOPHILANE DERIVATIVES This is adivision of application Ser. No. l 1 1,736 filed Feb. 1, 1971, now US.Pat. No. 3,819,711.

FIELD OF THE INVENTION Novel oxygenated bicyclic odorants.

RELATED APPLICATIONS This application claims priority from applicant'sSwiss Application 2394/70, filed Feb. 19, 1970.

DESCRIPTION OF THE PRIOR ART SUMMARY OF THE INVENTION The presentinvention is concerned with new compounds of the general formula whereinR and R signifies hydrogen or methyl, but at least one of the symbols R,or R signifies hydrogen, X represents one of the residues R isisopropyl, isopropenyl or isopropylidene and the symbol represents a C-Csingle bond or C=C double bond, their use as odorants and/or flavoringsas well as a process for their manufacture.

Formula I, as also all other formulae occurring in the description andin the claims, is menat to include all stereoisomers.

The above formula I includes as sub-groups the compounds of thefollowing formulae In 1b 2c where R R and R have the above significance.

The new compounds of formula I are distinguishet by interesting odorantand/or aroma properties, espe cially by fruit, wood, or floral notes.

The new compounds of formula I can be obtained ii accordance with theinvention by reacting a compoum of the formula II It optionally afterprior conversion into an enamine, wit] a compound of the formula andoptionally hydrogenating the reaction product 0 the formula to acompound of the formula l R1 R2 optionally reducing this compound to acompound 0 the formula a R R 2 or by optionally reducing the reactionproduct of for mula la to a compound of the formula a a, 3 n

R and R and R in formulae lald as well as II and 11] having thesignificance stated for formula I.

Compounds of formula II wherein R represents the methyl residue can bereacted with a ketone or formula II] wherein R, H according to the usualmethods of the Robinson annelation. As is known, the latter is abase-induced reaction.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the preferred embodiment ofthe reaction of a compound of formula II, wherein R is a methyl group,with a compound of formula III, wherein R, is hydrogen, the reaction isinduced by strong base. As bases there come into consideration, forexample: sodium methoxide or sodium ethoxide, potassium tert. butoxide,alkali metal hydrides (e.g. sodium hydride), alkali metal amides (e.g.sodium amide). A preferred base is sodium ethoxide.

The reaction is expediently effected in a solvent and with exclusion ofair and moisture, thus, for example, in an inert gas (e.g. nitrogen)atmosphere. Suitable solvents are polar anhydrous solvents, for exampleethers such as diethyl ether, tetrahydrofuran, etc, or alcohols such asalkanols (e.g. methanol, ethanol); a preferred solvent is ethanol.

The proportion of the compound of formula I] to the compound of formulaIII expediently amounts to approximately 1 l, although an excess ofcompound II] of up to about 10 times the weight of the compound isacceptable.

The reaction temperature expediently lies between about -10C and thereflux temperature of the solvent. Preferably, the reaction partners areinitially left at lower temperature, for example at ca. 5l0, andthereupon heated to reflux temperatures for several hours. The mixtureis thereupon cooled, expediently to ca room temperature. The reactionmixture is then treated with a strong base, for example the aqueoussolution of an alkali metal hydroxide such as NaOH, KOH, etc, suitable40-50% (by weight) aqueous alkali is used in an amount sufficient toachieve an alkali metal hydroxide concentration of between I andsuitably about 5 and thereafter once more heated to reflux temperature,whereby aldolisation and dehydration to a compound of formula la occurs.

The isolation of the reaction product can be carried out according tomethods which are known per se. For example, the reaction product istaken up in an organic solvent and the organic solution washed firstlywith dilute acid such as an NaH PO -solution. After washing neutral anddrying, the crude product can be purified by conventional methods suchas, for example, adsorption chromatography and/or distillation.

If, on the other hand, one starts from a compound of formula I] whereinR H, this compound is expediently first converted into an enamine bymeans ofa secondary amine.

As secondary amines there can, for example, be used:

Aliphatic secondary amines such as dialkylamines (e.g. diethylamine) orcyclic secondary amines such as, for example, morpholine, piperidine,pyrrolidine. Pyrrolidine is preferred. The conversion into the enaminecan in other respects be undertaken according to conventional methods,for example by reacting the ketone II with a secondary amine, optionallyin the presence of a catalyst such as, for example, p-toluene-sulphonicacid, in a water-withdrawing inert solvent (e.g. methylene chloride,benzene or toluene) at room temperature or, preferably, at elevatedtemperature (e.g. reflux temperature at the solvent).

The subsequent reaction of the enamine with the ketone of formula III isexpediently carried out in a solvent and with exclusion of air andmoisture. Suitable solvents are anhydrous solvents such as, for example,ethanol, dioxan, benzene, toluene, dimethylformamimde, etc; toluene andbenzene are preferred.

The proportion of enamine to ketone III expediently amounts toapproximately 1:], although the ketone [II can also be employed inexcess.

The reaction temperature is expediently the reflux temperature of thereaction mixture. The mixture is left, for example, for several hours atthis temperature. It is thereupon cooled, expediently to roomtemperature, and then a weak acid (e.g. an acetate buffer) is added. Theamine-cleavage can then be achieved by heating once more (e.g. to refluxtemperature).

The reaction product can be finally worked up as already describedabove.

The ketones of formula lb saturated in the ring can be obtained in amanner known per se by hydrogenation of the ring double bond of the a,B-unsaturated ketones of formula Ia, expediently by means of an alkalimetal (e.g. potassium, sodium, or, preferably, lithium) in liquidammonia and in the presence of a solvent such as an ether (e.g. diethylether, dioxan, dimethoxyethane, or, preferably, tetrahydrofuran. Aftercompleted reduction, a proton-donor (e.g. dilute hydrochloric acid,ammonium sulfate, or preferably ammonium chloride) is with advantageadded.

The secondary alcohols of formula Ic can be obtained in a manner knownper se by reduction of the ketones of formula lb, expediently usingreducing agents such as complex borohydrides (e.g. sodium borohydride)or complex aluminum hydrides, such as, for example, the preferredlithium aluminum hydride, and in the presence of a solvent such as anether (e.g. diethyl ether, dioxan or dimethoxyethane). The reactiontemperature expediently lies between about 0C and room temperature.

The B-unsaturated alcohols of formula Id can be obtained in a mannerknown per se by reduction of the keto group of a ketone Ia as alreadydescribed above. When using a complex borohydride, there is expedientlyused as a solvent an alcohol such as an alkanol (e.g. methanol, ethanolor, preferably, Z-propanol). When using a complex aluminum hydride, onthe other hand, there is preferably chosen an ether (e.g. diethyl etheror tetrahydrofuran),

The alcohols of formula Id can finally be converted into the alcohols offormula lc in a manner known per se by hydrogenation of thering-double-bond.

The compounds of this invention can be used as odorants for themanufacture of odorant compositions such as perfumess, or for perfumingcertain technical products, for example solid and liquid detergents,synthentic washing agents, cleaning agents, aerosols or cosmeticproducts of all kinds (e. g. soaps, lotions, bath additives, ointments,face milk and make up). These compounds can find use in perfumery on thebasis of their wood or floral notes. In odorant compositions the contentof compounds of Formula 1 can, for example, amount to 1 to 15%. Apreferred range is constituted by that of 2 to 8%. An addition of l to2% of such an odorant composition usually suffices for perfuming soaps,one of 2 to 4% for lotions (shaving lotion, face lotion, eau de cologne)and one of 0.3 to 5% for bath additives or shampoos.

On the basis of their fruit aroma properties, certain compounds canlikewise be used as aromatants for the aromatisation of foods anddelicacies as well as of drinks. 1n the aroma compositions theconcentration of the compound is from about 0.0l-1% by weight and in thefinal products containing them between 0.1-100 ppm, preferably fromabout 1 to about ppm.

Perfumistically particularly interesting compounds are:

6-isopropenyl-2,3,4,4a,5,6,7,8-octahydro-2- naphthalenone (green, woody,persistent note, reminiscent of vetivieryl acetate).

4a-methyl-6-isopropenyl-2,3,4,4a,5,6,7,8-octahydro- Z-naphthalenone(green, floral note reminiscent of vetiveryl acetate),

2-hydroxy-6-isopropylidene-2,3,4,4a,5,6,7,8- octahydro-2-naphthalene(flowery, woody, somewhat persistant note),

2-hydroxy-6-isopropyll ,2,3,4,4a,5 ,6,7,8,8a-decahydro-naphthalene,(vetiverol-rose note),6-isopropylidene-1,2,3,4,4a,5,6,7,8,8a-decahydro-2- naphthalenone(intensive, citrus-like, woody note),

Of particular interest as an aromatizing agent is 6- isoproyl- 1,2,3,4,4a,5,6,7,8,8a-decahydro-2- naphthalenone [citrus aroma (orange,grape-fruit)].

EXAMPLE 1 a. 1.5 g (65.1 m eq.) of sodium are dissolved at 68C in anitrogen atmosphere in 156 ml of absolute ethanol. (This nitrogenatmosphere is maintained during the whole of the following reactionduration). A solution of g (99 m mol) of2-methy1-4-isopropenylcyclohexanone in 63 ml of absolute ethanol is thenadded dropwise with stirring during minutes. The mixture is stirred for10 minutes and a solution of 10.2 g (145.5 mmol) of vinyl methyl ketonein 69 ml of absolute ethanol is thereupon added dropwise with stirringduring 60 minutes. The mixture is allowed to further stir at 68C for 12hours. The reaction mixture is thereupon held at reflux for 8 hours.After cooling to room temperature, this mixture is treated with 30 g of50% aqueous caustic soda. The mixture is thereupon firstly held at roomtemperature for 30 minutes, then at reflux for 1% hours. For the workingup, the reaction mixture is taken up in ether-ice, washed with a sodiumdihydrogen phosphate solution and a sodium chloride solution. It isdried over magnesium sulphate and the solvent is thereupon removed. g ofcrude mixture being obtained. This is filtered over the l0-fo1d amountof Silicage in benzene-hexane 4:1. There are obtained 22.5 g of aproduct which are subjected to a Vigreux distillation. The fraction withthe boiling point 1l1-1 l4C/0.4 Torr (5.5 g) represents 4a-methyl-6-isopropenyl-2,3,4,4a,5,6,7,8-octahydro-2- naphthalenone. n 1.5276; UVspectrum (ethanol) A 238 rim (6 15,600); 1R spectrum (CCl bands at1,675, 1,650, 1,625, 895 cm; NMR spectrum (CDCI 8= 1.26 ppm (s, 3H);1.75 ppm (s, 3H); 4.78 ppm (5, 2H); 5.85 ppm (5, 11-1). The substancehas a green, floral note and is reminiscent of vetiveryl acetate.

b. A solution of 1.049 g (5.13 mmol) of 4a-methyl-6-isopropenyl-2,3,4,4a,5,6,7,8-octahydro-2- naphthalenone in 16 ml ofabsolute tetrahydrofuran is added to a solution of 330 mg (47 m eq.) oflithium in 150 ml of liquid ammonia (distilled over sodium). Thereaction mixture is stirred at for 3 minutes and then treated with 3 gof solid ammonium chloride. After evaporating off the ammonia, theresidue is taken up in ether and the organic solution washed neutralwith water. After drying the ether phase with magnesium sulphate andsucking off the ether, there remain 1.019 g of an oil which, afterdistillation in the bulbtube, yield 933 mg of4a-methyl-6-isopropenyll,2,3,4,4a,5,6,7,8,Sa-decahydro-2-naphthalenonewith the boiling point 70C/0.005 Torr. u 1.5072; [R spectrum (CCl bandsat 1,720, 1,650, 895 cm; NMR spectrum (CDCl;,): 8 1.08 ppm and 1.27 ppm(s, 3H); 1.70 ppm and 1.85 ppm (s, 3H); 4.70 ppm and 4.85 ppm (s, 21-1).

The substance displays a woody, fresh-herby note and is reminiscent ofnootkatone.

According to the gas-chromatographic and NMR spectral data obtained, theisolated product exists as a mixture of 2 stereoisomers.

c. 152 mg (4 mmol) of lithium aluminium hydride were suspended in 8 mlof absolute ether and cooled to 0C. To this solution there is addeddropwise, in a nitro gen atmosphere and with stirring, a solution of 442mg (2 mmol) of4a-methyl-6-isopropenyll,2,3,4,4a,5,6,7,8,8a-decahydro-2-naphthalenonein 16 ml of absolute ether. The mixture is stirred at room temperaturefor 16 hours. The excess lithium aluminum hydride is decomposed bysuccessive dropwise addition in a nitrogen atmosphere of 0.15 ml ofwater, 0.15 ml of 15% aqueous caustic soda and 0.45 ml of water. For theworking up, the mixture (after stirring at 0C for 25 minutes) is takenup in ether/ice and the ethereal phase washed neutral with water. It isdried over magnesium sulphate and the solvent removed. There arerecovered 405 mg of an oil which, after bulbtube distillation, give 358mg of 2-hydroxy-4a-methyl-6 -isopropenyl-1,2,3,4,4a,5 ,6,7,8,8a-decahydronaphthalene with the boiling point 90C/0.00l Torr. u1.5121; IR spectrum (CCI), bands at 3,400, 1,650, 895 cm; NMR spectrum(CDCl;): 8 0.89 ppm. 0.98 ppm and 1.05 ppm (s, together 3H); 1.72 ppmand 1.81 ppm (s, 3H); 4.69 ppm and 4.84 ppm (s, 2H).

The substance displays a woody note.

According to the NMR spectral data obtained, the isolated product existsas a mixture of stereoisomers.

EXAMPLE 2 a. 138.2 g. (1.0 mol) of 4-isopropenyl-cyclohexanone and 78.1g (1.10 mol) of pyrrolidine are dissolved in 300 ml of absolute tolueneand held at reflux for 3 hours at the water-separator under a nitrogenatmosphere. Thereupon, by distilling off the solvent (250 ml) excesspyrrolidine is also removed. After cooling the residue, a solution of70.9 g (1.0 mol) of vinyl methyl ketone in 300 ml of absolute toluene isadded dropwise with nitrogen flushing and stirring during an hour. Thereaction mixture is thereupon held at reflux for 22 hours under anitrogen atmosphere. It is subsequently allowed to cool to roomtemperature and the reaction mixture is treated with an acetate buffersolution (37.2 g of anhydrous sodium acetate. 74 ml of water and 74 mlof glacial acetic acid); it is thereupon heated at reflux for a further4 hours. For the working up, the reaction mixture is cooled to roomtemperature and diluted with 400 ml of toluene. The aqueous phase isseparated off and the organic phase is successively washed with 2-Nhydrochloric acid, with saturated aqueous sodium bicarbonate solutionand with water and dried over magnesium sulphate. After removal of thesolvent, the crude mixture is distilled on a packed column. The fraction(76.3 g) with the boiling point l06-108C/0.5 Torr. represents6-isopropenyl- 2,3,4,4a,5.6,7,8-octahydro-Z-naphthalenone. 11 1.5291; UVspectrum (ethanol): A 238 nm (e 13.400); IR spectrum (CCl,,): bands at1,680, 1,650, 1,625, 900 cm NMR spectrum (CDCl:,): 8 1.76 ppm (s, 3H);4.79 ppm (5, 2H); 5.88 ppm (s, 1H).

The compound has a green, woody, persistent note and its odour isreminiscent of vetiveryl acetate.

b. 1.046 g (5.5 mmol) of 6-isopropenyl-2,3,4,4a,5,6,7,S-octahydro-2-naphthalenone, dissolved in 16 ml ofabsolute tetrahydrofuran, are added to a solution of 387 mg (55.3 m eq.)of lithium in 150 ml of liquid ammonia (distilled over sodium). Thereaction mixture is stirred at 70C for 4 minutes and then treated with3.5 g of solid ammonium chloride. After evaporating off the ammonia, theresidue is taken up in ether and washed neutral with water. After dryingthe ether phase with magnesium sulphate and sucking off the ether, thereremain 933 mg of an oil which, after distillation in the bulb-tube,yield 831 mg of 6 isopropenyl- 1 ,2,3,4,4a,5,6,7,8,8a-decahydro-2-naphthalenone with the boiling point 7080C/0.001 Torr. m, 1.5013; IRspectrum (CCl bands at 1,720, 1,650, 900 cm"; NMR spectrum (CDCl 5 1.73ppm (5, 3H); 4.72 ppm (5,211).

The substance displays a fruity, green note which is reminiscent ofcitrus peel, as well as a woody note in the direction of vetiver andbergamotte.

c. 760 mg (20 mmol) of lithium aluminum hydride are suspended in 42 mlof absolute ether. The mixture is cooled to and, in a nitrogenatmosphere and with stirring, a solution of 950 mg mmol) of 6-isopropenyl- 2. 3. 4. 4a, 5, 6, 7, 8, -octahydro-2 naphthalenone in 42ml of absolute ether is added dropwise. The mixture is stirred at roomtemperature for 16 hours. For the working up, the reaction mixture iscooled to 0 C and the excess lithium aluminum hydride destroyed byaddition of ethyl acetate; the mixture is thereupon taken up inether-ice and washed neutral with water. It is dried over magnesiumsulphate and the solvent removed. 930 mg of crude product beingobtained. After distillation at the bulb-tube, there can be isolated 900mg of 2-hydroxy-6-isopropenyl- 2,3,4,4a,5,6,7,S-octahydro-naphthalenewith the boiling point 95C/0.0l Torr. m, 1.5223; IR spectrum (CC1 bandsat 3,360, 1,650, 900 cm NMR spectrum CDCl;,): 8 1.72 ppm (s, 31-1); 4.70ppm (s, 2H); 5.43 ppm (s, 11-1).

The substance displays a marked floral note, reminiscent of roses, witha pleasant woody under-tone.

EXAMPLE 3 a. -isopropropylidene-cyclohexanene g (0.01 mol) of4-isopropylidene-cyclohexane and 1.42 g (0.02 mol) of pyrrolidine aredissolved in 7 ml of absolute benzene and held at reflux for 16 hoursunder nitrogen at the water-separator. After cooling, the benzene andthe excess pyrrolidine are removed by evaporation (water-jet vacuum/60C) and subsequent drying of the mixture in high vacuum for 1 hour at 25C. The residue (2.2 g) is dissolved in 4 ml of absolute benzene, treatedwith 0.7 g (0.01 mol) of vinyl methyl ketone and, under a nitrogenatmosphere and with stirring, held at reflux for 23 hours. Aftercooling, the mixture is treated with 0.9 ml of an acetate buffersolution g of anhydrous sodium acetate, 100 ml of water and 100 m1 ofglacial acetic acid) and held at reflux for 4 hours. For the working up,the mixture is taken up in ether-ice, washed twice with 2-N hydrochloricacid, twice with saturated aqueous sodium bicarbonate solution andthereupon again with water. The organic phase is dried over magnesiumsulphate and the solvent removed, 2.3 g of a crude mixture beingobtained. This is chromatographed on the 50-fold amount of silica gel.With benzene-ether 19:1, there can be eluted 0.38 g of crude productwhich, after distillation in the bulb-tube, gives 0.25 g of6-isopropylidene-2,3,4,4a,5,6,7,8-octahydro- 2-naphthalenone with theboiling point l00-105C/0.5 Torr. n 1.5445; UV spectrum (ethanol): A 234nm (e 13,500); IR spectrum (CCl bands at 1,680, 1,628 cm"; NMR spectrum(CDCl;,): 8 1.70 ppm (s, 6H): 5.86 ppm (s, 1H).

The compound has a pleasant a-vetivone-like odor.

b. 1.32 g (40 m mole) of lithium aluminum hydride are suspended in 80 mlof absolute ether in an nitrogen atmosphere and added, with ice coolingand stirring to a solution of 3.80 g (20 m mole) of fi-isopropylidene-2,3,4,4a,5,6,7,8-octahydro-Z-naphthalenone in 160 ml of absolute etherin a dropwise manner. The reaction mixture is stirred for 16 hours atroom temperature in a nitrogen atmosphere. The excess lithium aluminumhydride is destroyed by adding sequentially at 0C 1.5 ml of water, 1.5ml of 15% aqueous sodium hydroxyde and 4.5 m1 of water in a dropwisemanner, and stirring the resultant mass for a further 20 minutes. Theprecipitated material is removed by filtration, and the ethereal phaseis washed with saturated aqueous sodium chloride solution to neutrality,dried and the ether removed by distillation under reduced pressure. Theresidue (4.2 g) is distilled by short path distillation (0.04Torr/130C), to yield cristalline 2 -hydroxy-6-isopropylidene-2,3,4,4a,5,6,7,8-octahydronaphthalene (3.7 g) m.p. 6263C,l.R. (CCl bands at 3,630, 3,350 and 1,665 cm", MMR Spectrum (CDCl 8=1.70 ppm (s, 6H); 4.22 ppm (m, 1H); 5.43 ppm (m, 11-1).

The compound has a woody flowery odor of highly satisfactorypersistance.

c. 9.32 g (49 m mole) of 6-isopropylidene-2,3,4,4a,5,6,7,8-octahydro-2-naphthalenone, dissolved in ml of absoluteether are added slowly to a solution of 3.4 g (490 m seq.) of lithium in600 m1 of liquid ammonia previously distilled over sodium. Thetemperature of the reaction mixture is held at C for 15 minutes andstirred. The reaction is then quenched by adding thereto 30 q of solidammonium chloride. The ammonia is allowed to evaporate, the residuetaken up in ether and the ether layer washed to neutrality withsaturated aqueous sodium chloride solution. The ether layer is thendried over magnesium sulfate, filtered, and the ether evaporated toyield 9.6 g of residue which is then chromatographed on 500 g of silicagel. Elution with benzene/ether (19:1) yields 4.9 g of product which,upon shortpath distillation yields 4.70 g of 6- isopropylidene-l,2,3,4,4a,5 ,6,7,8,8a-decahydro-2- naphthalenone b.p. 95-100C/0.01 Torr.n 1.5102; lR Spectrum (CCl bands at 1,715 cm NMR Spectrum (CDCl );5 1.70ppm (s, 6H).

The compound has an intensive citrus-like woody odor.

EXAMPLE 4 a. 13.8 g (0.1 mole) of 4-isopropenyl'cyclohexanone and 14.2 g(0.2 mole) of pyrrolidine, dissolved in 70 ml of absolute benzene, areheld at reflux for 16 hours under a nitrogen atmosphere at thewater-separator. After cooling the mixture, benzene and excess pyrrolidine are removed by evaporation (water-jet vacuum/60C) and subsequentdrying in high vacuum at 25C for 1 hour. The residue (16 g) is dissolvedin 40 ml of absolute toluene, treated with 9.2 g (0.1 mole) of3-penten-2-one and held at reflux under a nitrogen atmosphere and withstirring for 23 hours. After cooling, the mixture is treated with 9 mlof an acetate buffer solution (50 g of anhydrous sodium acetate, 100 mlof water and 100 ml of glacial acetic acid) and held at reflux for 4hours. For the working up, the reaction mixture is taken up inether-ice, washed twice with 2N hydrochloric acid, twice with saturatedaqueous sodium bicarbonate solution and finally again with water. It isdried over magnesium sulfate and the solvent removed, 25 g of a crudemixture being obtained. This is filtered over the 10-fold amount ofsilica gel in benzene-ether 19:1, there being isolated 4 g of crudeproduct which, after distillation in the bulb-tube yield 2.92 g of 4-methyl-6-isoprpenyl-2,3,4,4a,5,6,7,8-octahydro-2 naphthalenone with theboiling point 100l lC/0.03 Torr. n0 1.5247; UV spectrum (ethanol): A at238 mm (s 14,170); IR spectrum (CCl bands at 1,680, 1,650, 1,638 cm, 900cm; NMR spectrum (CDCl;,): 8 1.05 ppm (b,3H); 1.76 ppm (5,3H); 4.76 ppm(s,2H); 5.85 ppm (s,1H). According to the latter data, with the productit is a case ofa mixture of stereoisomers.

This mixture smells markedly green, woody and cedarlike.

b. 760 mq (20 m mole) of lithium aluminum hydride are suspended in 42 mlof absolute ether. The mixture is cooled to 0C and, in a nitrogenatmosphere and with stirring, a solution of 1.0 g (m mole) of4-methyl-6- isopropenyl-2,3,4,4a,5,6,7,8-octahydro-2- naphthalenone in42 ml of absolute ether is added dropwise. The mixture is thereuponstirred at room temperature for 16 hours. It is thereupon cooled to 0Cand the excess lithium aluminum hydride destroyed by addition of ethylacetate. For the working up, the mixture is taken up in ether-ice andwashed neutral with water. The organic phase is dried over magnesiumsulfate and the solvent removed. There are thus obtained 1.01 g of anoil which, after bulb-tube distillation, yield 816 mg of2-hydroxy-4-methyl-6-isopropenyl- 2,3,4,4a,5,6,7,8-octahydro-naphthalenewith the boiling point 125130C/0.15 Torr. n 1.5122; IR spectrum (CClbands at 3,350, 1,650, 900 cm; NMR spectrum (CDCI 6 0.97 ppm (b, 3H);1.72 ppm (s,3H); 4.70 ppm (s, 2H); 5.39 ppm (s, 1H).

The substance smells woody, slightly earthy and is reminiscent of guaiacand sandalwood. According to the NMR data obtained, the isolated productexists as a mixture of stereoisomers.

EXAMPLE 5 a. 140.2 g (1 mole) 4-isopropyl cyclohexanone and 90.2 g ofpiperidine (1.06 mole) are placed in a 2 litre round bottomed flaskequipped with stirrer, cooler, thermometer and Dean-Stark and Barretttrap and water remover. 400 ml of toluene are added and the mixtureheated under reflux for 6 hours. After this time no further separationof water is noted. The excess piperidine and toluene are removed bydistillation. After distillation of approximately 250 ml substantiallyall of the piperidine has been removed. The apparatus is then flushedwith nitrogen for about 10 minutes, and a solution of 70.9 g (1 mole) ofmethylvinyl ketone in 300 ml of toluene is added dropwise over a periodof 30 minutes. During the addition temperature rises to about 65C. Themixture is then heated under reflux and in a nitrogen atmosphereapproximately 24 hours. The mixture is then cooled to 25C and 400 ml of20% aqueous hydrochloric acid added thereto. The mixture is then heatedfor 4 hours at between and C and cooled to ambient temperature. 800 mlof toluene are added, the layers separated, and the organic layer washedsequentially with m1 of 10% aqueous sodium carbonate, and four timeswith 100 ml portions of water. The organic layer is dried, andevaporated to yield a residual organic material. The residue isdistilled through a column charged with glass beads. After approximately28.7 grams of pre-run have distilled over,6-isopropy1-2,3,4,4a,5,6,7,8-octahydro-2- naphthalenone (54.6 g)distills over in the range of 109 to C/0.75-lmmHg; n l.5l51.520. Thepurity of the material is 97% (gas chromatography shows the presence of2 isomers.

b. m1 of distilled water, 150 ml of p-dioxane and 20 g ofsodiumborohydride (0.58 mole) are charged to a 500 ml round bottomedflask equipped with stirrer, cooler, dropping funnel, and thermometer.There are added thereto 48.1 g (0.25 mole) of 6-isopropyl-2,3,4,4a,5,6,7,8-octahydro-2-naphthalenone in a dropwise fashion over aperiod of 30 minutes during which time the reaction vessel is cooled tomaintain a temperature of between 25 to 30C. The reaction is held atthis temperature for 4 hours with stirring. The reaction mixture isthereupon extracted with 350 ml of ether, and the ether layer washedtwice with 100 ml portions of water, dried over magnesium sulfate,filtered, and the extract evaporated under reduced pressure.Distillation of the residue through a column packed with glass beadsyields 34.2 g of 2-hydroxy-6-isopropyl-2,3,4,4a,5,6,7,8-octahydro-naphthalene (yield: 77%) b.p. l l2-l l4C/0.9mm, n 1.5049.

c. 78 g (0.4 mole) of 6-isopropyl-2,3,4,4a,5,6,7,8-octahydro-2-naphthalenone are hydrogenated in 150 ml of ethanol in thepresence of 8g of 5% palladium on charcoal, under a hydrogen pressure of2 atmospheres. The reaction is complete in 30 minutes. The reactionmixture is suction-filtered through a Super-eel bed and the residuewashed with ethanol. The ethanol solutions are mixed and evaporatedunder reduced pressure. Distillation of the residue through a columnpacked with glass beads yields 60 grams (76% yield) offi-isopropyll,2,3,4,4a,5,6,7,8,8a-decahydro-2-naphthalenone, b.p. 8889%0.4 mm. n 1.4884.

d. A 500 ml round bottomed flask equipped with stirrer, thermometer,external cooling, and a dropping funnel is flushed with nitrogen. Anitrogen atmosphere is maintained and 2.3 g (0.06 mole) of lithiumaluminum hydride and 250 ml of dry ether are added thereto. 38.8 g (0.2mole) of 6-isopropyl-l,2,3,4,4a,5,6,7,8,8a decahydro-Z-naphthalenoneadded dropwise over a period of l hour while maintaining the reactionvessel at 2530C by external cooling. Cooling is maintained for a further4 hours and the reaction mixture stirred at the given temperature. Undercontinued cooling a saturated aqueous solution of sodium sulfate isadded thereto until the thus formed gray-colored precipitateredissolves. The reaction mixture is filtered and residual material iswashed with ether. The ether layer is washed with 2 portions of 100 mlsaturated sodium chloride solution, dried over magnesium sulfate,filtered and concentrated by evaporation of the solvent under reducedpressure. The residual material is fractionally distilled through acolumn packed with glass beads to yield2-hydroxy-6isopropyll,2,3,4,4a,5,6,7,8,Sa-decahydronaphthalene as anisomeric (epimeric) mixture b.p. 94 to 99C/0.40.6 mmHg, (27.7 g), 71%yield, 11 1.4954.

EXAMPLE 6 a. 2.52 g (46.4 mmol) of dried sodium methylate are suspendedin 4C ml of absolute benzene. With stirring, this suspension is treatedwith a solution of 3.44 g (46.4 mmol) of absolute formic acid ethylester in 25 ml of absolute benzene. After stirring for 30 minutes, asolution of 3.2 g (23.2 mmol) of 4-isopropylidene cyclohexanone in 15 mlof absolute benzene is added dropwise. The mixture is thereupon furtherstirred for 18 hours in a nitrogen atmosphere at room temperature. Forthe working up, the suspension is treated with ice-cold 2-N hydrochloricacid up to the weakly acidic reaction; the crude mixture thus obtainedis taken up in methylene chloride, washed neutral with a common saltsolution, the organic phase dried with magnesium sulphate and evaporatedto dryness. There are obtained 3.5 g (21 mol) of2-hydroxymethylene-4-isopropylidene-cyclohexanone [IR spectrum (CClbands at 1,660; 1,595 cm which after drying in high vacuum can bedirectly further processed. 3.5 g (21 mmol) of2-hydroxymethylene-4-isopropylidene-cyclohexanone are dissolved in 30 mlof absolute acetone and treated with 7.7 g (55.5 mmol) of anhydrouspotassium carbonate. A solution of 15.3 g (108 mmol) of methyl iodide in29 ml of absolute acetone is added dropwise. With exclusion of light andin a nitrogen atmosphere, the reaction mixture is stirred at roomtemperature for 18 hours. For the working up, it is firstly filtered offfrom potassium carbonate and the filtrate concentrated (40C/water-jetvacuum). The crude product is poured onto ether-ice and the organicphase washed neutral with a sodium chloride solution. After drying overmagnesium sulphate and evaporation of the solvent, there are obtained3.6 g (20 mmol) of 2-formyl-2-methyl-4- isopropylidene-cyclohexanone [IRspectrum (CCl bands at 2,750, 1,740, 1,710 cm" which are suitable forfurther processing. 1.7 g (42.5 mmol) ofsodium hydroxide are dissolvedin 17 ml of water and 30 m1 of methanol. A solution of 3.6 g (20 mmol)of 2-formyl-2- methyl-4-isopropylidene-cyclohexanone in 21 ml ofmethanol is added thereto. The mixture is stirred for 1 hour at roomtemperature in a nitrogen atmosphere.

For the working up, the reaction mixture is taken up in ether/ice,washed with 2-N caustic soda then with saturated common salt solution,the organic phase is dried with magnesium sulphate and evaporated todryness. There are obtained 4 g of a crude product which, afterdistillation in the bulb-tube, give 1.6 g of 2-methyl-4-isopropylidene-cyclohexanone with the boiling point 1101 15/1l Torr. n1.4828; IR spectrum (CCl band at 1,720 cm. NMR spectrum (CHCl 8= 1.08ppm (d, 3H, .1 6 cps); 1.74 ppm (s, 6H).

b. Starting from 2 -methyl-4-isopropylidenecyclohexanone, by annelationwith vinyl methyl ketone analogously to Example 1 there can be obtained40- methyl-6-isopropylidene-2,3,4,4a,5,6,7,8-octahydro-2- naphthalenonewith the boiling point C/0.01 Torr. UV spectrum (ethanol): A 233 nm (e12,600). IR spectrum (CCl bands at 1,680 and 1,628 cm". NMR spectrum(CDC1 8 1.15 ppm (s, 3H); 1.73 ppm (s, 6H); 5.75 ppm (s, 1H). Thecompound displays a woody note in the direction of vetiver.

EXAMPLE 7 1.33 g (9.65 mmol) of 4-isopropylidenecyclohexanone and 1.62ml (20 mmol) of pyrrolidine are dissolved in 7 ml of absolute benzene;the mixture is held at reflux for 16 hours in a nitrogen atmosphere atthe water-separater. After cooling, benzene and excess pyrrolidine areremoved by evaporation (water-jet vacuum/60C) and subsequent drying inhigh vacuum at 25"C for 1 hour. The residue (1.8 g) is dissolved in 4 mlof absolute toluene, the solution is treated at room temperature with1.26 g (15 mmol) of 3-penten-2-one and held at reflux in a nitrogenatmosphere and with stirring for 23 hours. After cooling, the mixture istreated with 0.9 ml of an acetate buffer solution (50 g of anhydroussodium acetate, 100 ml of water and 100 ml of glacial acetic acid) andheld at reflux for 4 hours. For the purpose of working up, the mixtureis taken up in ether/ice, washed once with ice-cold 2-N hydrochloricacid then 3 times with saturated common salt solution. The organicsolution is dried over magnesium sulphate and the solvent removed, 1.6 gof a crude mixture being obtained. This is chromatographed on the50-fold amount of Silica gel. With benzene-ether 19:1, there can beeluted 0.29 g of crude product which, after distillation in thebulb-tube, give 0.21 g of4-methyl-6-isopropylidene-2,3,4,4a,5,6,7,8-octahydro- 2-naphthalenonewith the boiling point 1 10/0.01 Torr. n 1.5371; IR spectrum (CCl bandsat 1,680, 1,628 cm; UV spectrum (ethanol): u =232 nm (e 13,400); NMRspectrum (CDC1 5 1.10 ppm (d,

=6 cps, 3H); 1.71 ppm (s, 6H); 5.85 ppm s, 1H). The substance has afloral note in the direction of rose, and is reminiscent of citronellol.

EXAMPLE 8 Odorant composition (Gardenia type) Parts by weight6-lsopropeny1-2,3,4,4a,5,6,7,8

Nonalactone 10% in phthalic acid -Continued diethyl ester 5-y-Undecalactone in phthalic acid diethyl ester 2 Hydroxycitronellal 30Linalool 5 Heliotro in Citronel ol laevo 20 EXAMPLE 9 Odorantcomposition (Eau de Cologne parfumEc)4a-Methyl-6-isopropenyl-2,3,4,4a,5,6,

Parts by weight 7,8-octahydro-2-naphthalenone 50 Basil oil 5 l5 Estrogenoil 5 Galbanum oil 5 Coriander oil 10 Undecylenealdehyde 10% in phthalicacid diethyl ester 10 Methylnonylacetaldehyde 10% in phthalic aciddiethyl ester 10 20 Sauge sclarEe l0 Vetiver oil Bourbon 20 Eugenol l0Mousse dc Cherie sol. l0 Bergamotte oil Reggio 250 Lemon oil (Spanish)80 Orange oil (Californ.) 50 25 Lavender oil Jasmine type odorant 5Cedryl acetate cryst. Santalol 20 4-Mcthyl-7-ethoxycoumarin 10% phthalicacid diethyl ester 20 30 Res. labdanum 10 650 EXAMPLE l0 Citrus colognefragrances were prepared utilizing 4 of the compounds of the presentinvention. The compositions are set forth in Table 1 below. For the sakeof brevity the compounds have been designated by letters as follows:

A. 6-isopropyl-2,3,4,4a,5,6,7,8-octahydro-2- naphthalenone.

B. Z-hydroxy--isopropyl-2,3,4,4a,5,6,7,8- octahydro-2-naphthalene.

C. 6-isopropyll ,2,3,4,4a,5,6,7,8,8a-decahydro-2- naphthalenone.

" Registered trademark of Givaudan Corporation for hydroxycitronellal.

" Registered trademark of Givaudan Corporation for isocamphylcyclohexanol (US. Pat. No. 3.499.937).

Registered trademark of Givaudan Corporation 1.],4.4-tetramethyb6ethyl-7-acetyll ,2,3,4-tctrahydronaphthalene.

for

In formulation (i) it was found that 1% of Compound A contributes apleasing warm citrus nuance which enhances the citrus character of thefragrance during dry out.

[n formulation (ii) it was found that 4% of Compound B contributes awarm woody rose character which makes the fragrance much more pleasing.

In formulation (iii) it was found that 0.5% of Compound C contributes anoutstanding citrus nuance and also lend substantial lift" to thefragrance The fragrance with Compound C is far superior to that withoutCompound C.

In formulation (iv) it was found that l% of Compound D contributes verypleasing warm woody floral nuance which is not unlike that which wouldbe produced by vetiverol. The fragrance with Compound D is far superiorto that without Compound D.

We claim:

1. A compound of the general formula wherein R and R signify hydrogen ormethyl, but at least one of the symbols R and R signifies hydrogen, andR is isopropyl, isopropenyl or isopropylidene.

2. 4a-Methyl-6-isopropenyl-2,3.4,4a,5,6,7,8- octahydro-Z-naphthalenone.

3. 6-lsopropenyl-2,3,4,4a,5,6,7,8-octahydro-2- naphthalenone.

4. 6-lsopropyl-2,3,4,4a,5,6,7,8-octahydro-2- naphthalenone.

1. A COMPOUND OF THE GENERAL FORMULA 2.4a-Methyl-6-isopropenyl-2,3,4,4a,5,6,7,8-octahydro-2-naphthalenone. 3.6-Isopropenyl-2,3,4,4a,5,6,7,8-octahydro-2-naphthalenone. 4.6-Isopropyl-2,3,4,4a,5,6,7,8-octahydro-2-naphthalenone.